Due to the increased use of a magnetic recording medium with wide variation, it has become necessary to develop a magnetic recording medium having excellent characteristics in the short wavelength region. This requirement has increased with the demand for improving video tapes, audio tapes, tapes for computers or floppy discs.
Therefore, it is necessary that an axis of easy magnetization of ferromagnetic particles be perpendicular to a surface of a magnetic recording layer. Various studies were made for orienting acicular particles in a magnetic field perpendicular to a recording surface, as disclosed in U.S. Pat. No. 3,052,567. However, the orientation of the particles often tends to be disturbed during drying. Also, an attempt was made to orient plate-shaped particles such as Ba-ferrite type particles having an axis of easy magnetization perpendicular to the plate thereof instead of the acicular particles in a magnetic field perpendicular to a recording surface, but the orientation of the particles was also disturbed during a drying step.
That is, it was clear that the highly oriented ferromagnetic particles in a coated magnetic coating composition are disturbed during the drying step thereby deteriorating the excellent orientation.